Re: [PATCHES] [SQL] Interval subtracting
Attached is the new patch. To summarize: - new function justify_interval(interval) - modified function justify_hours(interval) - modified function justify_days(interval) These functions are defined to meet the requirements as discussed in this thread. Specifically: - justify_hours makes certain the sign bit on the hours matches the sign bit on the days. It only checks the sign bit on the days, and not the months, when determining if the hours should be positive or negative. After the call, -24 hours 24. - justify_days makes certain the sign bit on the days matches the sign bit on the months. It's behavior does not depend on the hours, nor does it modify the hours. After the call, -30 days 30. - justify_interval makes sure the sign bits on all three fields months, days, and hours are all the same. After the call, -24 hours 24 AND -30 days 30. 'make check' passes all tests. There are no tests for justify_interval, as it is new. But the existing tests for justify_hours and justify_days appear to still work, even though the behavior has changed. Apparently, their test cases are not sensitive to the particular changes that have occurred. I would include new tests in the patch but do not know on which reference machine/platform the patches are supposed to be generated. mark Index: src/backend/utils/adt/timestamp.c === RCS file: /projects/cvsroot/pgsql/src/backend/utils/adt/timestamp.c,v retrieving revision 1.160 diff --context -r1.160 timestamp.c *** src/backend/utils/adt/timestamp.c 22 Nov 2005 22:30:33 - 1.160 --- src/backend/utils/adt/timestamp.c 3 Mar 2006 20:23:26 - *** *** 1975,1980 --- 1975,2054 } /* + * interval_justify_interval() + * + * Adjust interval so 'month', 'day', and 'time' portions are within + * customary bounds. Specifically: + * + *0 = abs(time) 24 hours + *0 = abs(day) 30 days + * + * Also, the sign bit on all three fields is made equal, so either + * all three fields are negative or all are positive. + */ + Datum + interval_justify_interval(PG_FUNCTION_ARGS) + { + Interval *span = PG_GETARG_INTERVAL_P(0); + Interval *result; + + #ifdef HAVE_INT64_TIMESTAMP + int64 wholeday; + #else + double wholeday; + #endif + int32 wholemonth; + + result = (Interval *) palloc(sizeof(Interval)); + result-month = span-month; + result-day = span-day; + result-time = span-time; + + #ifdef HAVE_INT64_TIMESTAMP + TMODULO(result-time, wholeday, USECS_PER_DAY); + #else + TMODULO(result-time, wholeday, (double) SECS_PER_DAY); + #endif + result-day += wholeday;/* could overflow... */ + + wholemonth = result-day / DAYS_PER_MONTH; + result-day -= wholemonth * DAYS_PER_MONTH; + result-month += wholemonth; + + if (result-month 0 result-day 0) + { + result-day -= DAYS_PER_MONTH; + result-month++; + } + else if (result-month 0 result-day 0) + { + result-day += DAYS_PER_MONTH; + result-month--; + } + + if (result-time 0 result-day 0) + { + #ifdef HAVE_INT64_TIMESTAMP + result-time += USECS_PER_DAY; + #else + result-time += (double) SECS_PER_DAY; + #endif + result-day--; + } + else if (result-time 0 result-day 0) + { + #ifdef HAVE_INT64_TIMESTAMP + result-time -= USECS_PER_DAY; + #else + result-time -= (double) SECS_PER_DAY; + #endif + result-day++; + } + + PG_RETURN_INTERVAL_P(result); + } + + /* *interval_justify_hours() * *Adjust interval so 'time' contains less than a whole day, adding *** *** 2006,2011 --- 2080,2104 #endif result-day += wholeday;/* could overflow... */ + if (result-time 0 result-day 0) + { + #ifdef HAVE_INT64_TIMESTAMP + result-time += USECS_PER_DAY; + #else + result-time += (double) SECS_PER_DAY; + #endif + result-day--; + } + else if (result-time 0 result-day 0) + { + #ifdef HAVE_INT64_TIMESTAMP + result-time -= USECS_PER_DAY; + #else + result-time -= (double) SECS_PER_DAY; + #endif + result-day++; + } + PG_RETURN_INTERVAL_P(result); } *** *** 2031,2036 --- 2124,2140 result-day -= wholemonth * DAYS_PER_MONTH; result-month += wholemonth; + if (result-month 0 result-day 0) + { + result-day -= DAYS_PER_MONTH; + result-month++; + } + else if (result-month 0 result-day 0) + { + result-day +=
Re: [PATCHES] [SQL] Interval subtracting
Mark Dilger wrote: Mark Dilger wrote: Tom Lane wrote: Milen A. Radev [EMAIL PROTECTED] writes: Milorad Poluga напи�а: SELECT '10 years 1 mons 1 days'::interval - '9 years 10 mons 15 days'::interval ?column?--- 3 mons -14 days Why not '2 mons 16 days' ? Please read the last paragraph in section 8.5.1.4 of the manual (http://www.postgresql.org/docs/8.1/static/datatype-datetime.html#AEN4775) . It mentions the functions named justify_days and justify_hours that could do what you need. justify_days doesn't currently do anything with this result --- it thinks its charter is only to reduce day components that are = 30 days. However, I think a good case could be made that it should normalize negative days too; that is, the invariant on its result should be 0 = days 30, not merely days 30. Similarly for justify_hours. Comments anyone? Patch anyone? Sure, if nobody objects to this change I can write the patch. mark I've modified the code and it now behaves as follows: select justify_days('3 months -12 days'::interval); justify_days 2 mons 18 days select justify_days('3 months -33 days'::interval); justify_days --- 1 mon 27 days select justify_hours('3 months -33 days -12 hours'::interval); justify_hours --- 3 mons -34 days +12:00:00 select justify_days(justify_hours('3 months -33 days -12 hours'::interval)); justify_days 1 mon 26 days 12:00:00 select justify_hours('-73 hours'::interval); justify_hours --- -4 days +23:00:00 select justify_days('-62 days'::interval); justify_days -- -3 mons +28 days I find the last two results somewhat peculiar, as the new functionality pushes the negative values upwards (from hours to days, days to months). Changing '-73 hours' to '-3 days -1 hour' might be more intuitive? The '-4 days +23 hours' is however consistent with the behavior in the other cases. Thoughts? I will package this up into a patch fairly soon. mark The patch is attached. Since the functionality is being intentionally changed, not surprisingly the regression tests for timestamp, timestamptz and horology failed. The regression.diffs are also attached. I intended to update the docs for justify_days and justify_hours, but the docs don't detail the behavior at a sufficient level for any change to be warranted. mark Index: src/backend/utils/adt/timestamp.c === RCS file: /projects/cvsroot/pgsql/src/backend/utils/adt/timestamp.c,v retrieving revision 1.160 diff --context=5 -r1.160 timestamp.c *** src/backend/utils/adt/timestamp.c 22 Nov 2005 22:30:33 - 1.160 --- src/backend/utils/adt/timestamp.c 1 Mar 2006 18:35:36 - *** *** 2003,2013 TMODULO(result-time, wholeday, USECS_PER_DAY); #else TMODULO(result-time, wholeday, (double) SECS_PER_DAY); #endif result-day += wholeday;/* could overflow... */ ! PG_RETURN_INTERVAL_P(result); } /* *interval_justify_days() --- 2003,2021 TMODULO(result-time, wholeday, USECS_PER_DAY); #else TMODULO(result-time, wholeday, (double) SECS_PER_DAY); #endif result-day += wholeday;/* could overflow... */ ! if (result-time 0) ! { ! #ifdef HAVE_INT64_TIMESTAMP ! result-time += USECS_PER_DAY; ! #else ! result-time += (double) SECS_PER_DAY; ! #endif ! result-day--; ! } PG_RETURN_INTERVAL_P(result); } /* *interval_justify_days() *** *** 2028,2037 --- 2036,2050 result-time = span-time; wholemonth = result-day / DAYS_PER_MONTH; result-day -= wholemonth * DAYS_PER_MONTH; result-month += wholemonth; + if (result-day 0) + { + result-day += DAYS_PER_MONTH; + result-month--; + } PG_RETURN_INTERVAL_P(result); } /* timestamp_pl_interval() *** ./expected/timestamp.outSat Jun 25 20:04:18 2005 --- ./results/timestamp.out Wed Mar 1 10:21:00 2006 *** *** 442,448 SELECT '' AS 54, d1 - timestamp without time zone '1997-01-02' AS diff FROM TIMESTAMP_TBL WHERE d1 BETWEEN '1902-01-01' AND '2038-01-01'; 54 | diff ! + | @ 9863 days ago | @ 39 days 17 hours 32 mins 1 sec | @ 39 days 17 hours 32 mins 1 sec --- 442,448 SELECT '' AS 54, d1 - timestamp without time zone '1997-01-02' AS diff FROM TIMESTAMP_TBL WHERE d1 BETWEEN '1902-01-01' AND '2038-01-01'; 54 | diff ! +--- | @ 9863 days ago | @ 39 days 17 hours 32 mins